title: Metabolic nitrite formation from N-nitrosamines: evidence for a cytochrome P-450 dependent reaction.
abstract: Nitrite was formed on incubation of N-nitrosamines with a reconstituted monooxygenase system, consisting of cytochrome P-450 (P-450) and NADPH P-450 reductase from pig liver. Nitrite was not obtained when the nitrosamines were incubated with NADPH P-450 reductase alone or when molecular oxygen or NADPH were omitted. Interaction of nitrosamines with the reconstituted P-450 system or with hemoglobin under reducing conditions resulted in optical spectra identical with those obtained with nitrite. It is proposed that N-nitrosamines are denitrosated by electron transfer from the hemoprotein iron to the nitrosamine molecule.
mesh_terms: D000818:Animals; D001711:Biotransformation; D055598:Chemical Phenomena; D002621:Chemistry; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D009573:Nitrites / Q000032:analysis / Q000096:biosynthesis*; D009602:Nitrosamines / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D013056:Spectrophotometry, Ultraviolet; D013552:Swine
chemical_list: D006454:Hemoglobins; D009573:Nitrites; D009602:Nitrosamines; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase